I’ve recently gotten back into making jewelry after a ten-year
hiatus (silver only, at this point), and have started to re-supply
myself. I have a small Lortone tumbler that I bouht in February.
It’s exactly the same as the one I had ten years ago, and I never
once had a problem with it. I looked at the archives, and my search
didn’t find anything like the problem I’m having now, so I hope
someone can help me.

I’ve been using this new tumbler since I bought it in February, and
it’s been working beautifully for me up until now. Just last week I
put some pieces in, and an hour later both the silver and the shot
were covered with an almost waxy gray residue.

This coating washes off easily with soap and water, but the finish on
the pieces doesn’t seem to be as bright as it usually is. I tried
running just the shot with water and some dish soap, and the shot
cleaned right up.

I then tried tumbling some silver with the shot and basic burnishing
compund (same stuff I’ve been using since Feb,), and the residue was
back. I cleaned up the shot again and tried tumbling the silver with
dish soap and water. The residue was back, but not as bad. I cleaned
the shot up again with soap and water, then tried running just the
shot, overnight, with the burnishing compound. When I opened the
barrel this morning there was no foam at all, and the residue was
back as bad as the first time. Again, ran the shot with soap and
water, again, cleaned up pretty well. Maybe not quite as bright as
with a commercial shot cleaner (of which I have none on hand or I
would have tried it,) but definitely much cleaner.

At this point I’m at a loss. It seems to clean up pretty well with
soap and water, but every time I use the burnishing compound the
residue is back. I have not changed anything I’m doing, save having
added an additional 2lbs of shot, bringing my total up to 3lbs.

Could the problem be your water supply? Particularly hard water or
something? Have you tried running a few loads using distilled water
to see if it still happens? It might at least eliminate your water
supply as a source of the problem.